1. Field of the Invention
The present invention relates generally to a discharge display apparatus of the flat panel type, and method of manufacturing of this apparatus, and is directed more particularly to a so-called DC type discharge matrix display apparatus in which a pair of anode electrodes and cathode electrodes of discharge electrodes are respectively made of parallel electrode groups arranged in row and column directions, both electrode groups oppose each other with a predetermined distance and the discharge glow at the opposing portion between the electrodes of both electrode groups serves to perform a glow display.
2. Description of the Prior Art
As shown in FIGS. 1 and 2, a prior art DC type discharge matrix display apparatus is formed of a flat envelope 1 which consists of two substrates 2 and 3, each being formed, for example, of a glass plate, with discharge electrodes, etc., disposed therein. In this case, one of the substrates 2 and 3, the substrate 2 in the illustrated example is made of a glass plate which is light permeable or transparent. Both substrates 2 and 3 face each other and their peripheral edge portions are sealed up by, for example, frit glass 4 to define a flat glow space 5 between the two substrates 2 and 3 in which the flat glow space 5 is sealed up by a rare gas.
On the inner surface of one substrate, for example, substrate 3, is coated an electrode group Y which serves as a cathode and is formed of a plurality of parallel electrodes Y.sub.1, Y.sub.2, Y.sub.3, . . . , each arranged in one direction, for example, in a row direction with a predetermined distance between adjacent ones and having a necessary width. An insulating group of barriers G are also formed on the inner surface of the substrate 3 on which the electrode group Y are formed. The insulating group of barriers G are formed of a plurality of insulating projection barriers g.sub.1, g.sub.2, g.sub.3, . . . with each arranged in the direction perpendicular to the extending direction of the respective electrodes Y.sub.1, Y.sub.2, Y.sub.3, . . . of the cathode electrode group Y with a predetermined distance between adjacent ones and having a necessary width. In this case, the height of each of the projection barriers g.sub.1, g.sub.2, g.sub.3 . . . is selected in response to the space between the substrates 2 and 3.
On the inner surface of the other substrate 2, are coated a group of anode electrodes X which consist of a plurality of parallel electrodes x.sub.1, x.sub.2, x.sub.3 . . . , each being arranged in the direction substantially perpendicular to the extending direction of each of the parallel electrodes Y.sub.1, Y.sub.2, Y.sub.3, . . . , forming the cathode electrode group Y and having a predetermined width.
In this case, the respective anode electrodes x.sub.1, x.sub.2, x.sub.3, . . . , of the anode electrode group X are separated by the respective projection barriers g.sub.1, g.sub.2, g.sub.3, . . . of the group of insulating projection barriers G to define band-shaped spaces 5a, 5b, 5c, . . . in the space 5 to prevent the diffusion of the glow from being extended along each of the cathode electrodes Y.sub.1, Y.sub.2, Y.sub.3, . . . . When ON voltage is applied, for example, to the respective electrodes Y.sub.1, Y.sub.2, Y.sub.3, . . . , of the cathode electrode group Y in a time-division multiplex manner while ON voltages in response to the display signals are applied to the respective electrodes x.sub.1, x.sub.2, x.sub.3, . . . of the anode electrode group X sequentially or simultaneously, glow or light emissions with brightnesses in response to the voltage differences according to the display signals are effected to produce a light picture image in dot-sequence or line-sequence to thereby produce a display.
In general, with the above kind of a display apparatus, the respective electrodes x.sub.1, x.sub.2, x.sub.3, . . . of the anode electrode group X are located substantially at the center of the respective discharge or glow spaces 5a, 5b, 5c, . . . and the light emission or glow is observed from the anode electrode side. In this case, if the respective electrodes x.sub.1, x.sub.2, x.sub.3 . . . of the anode electrode group X are each made of a transparent electrode, a bright display can be realized. However, since such a transparent electrode has a high electrical resistance, if the anode electrode is made of such transparent electrode, it does not produce a preferred uniform brightness. Therefore, in this kind of the display apparatus, the electrodes at the observing side are generally made of opaque electrodes which have less electrical resistance. Normally, the arranging pitch of the light emission or glow portions or discharge spaces 5a, 5b, 5c, . . . is selected to be about 200 .mu.m. In this case, the respective electrodes x.sub.1, x.sub.2, x.sub.3, . . . of the anode electrode group X at the observing side and the respective barriers g.sub.1, g.sub.2, g.sub.3, . . . are generally formed by a printing method, so that the width of the anode electrodes is 70 .mu.m. However, since the height of the respective barriers g.sub.1, g.sub.2, g.sub.3, . . . must be rather high, for example, 100 to 150 .mu.m, the printing method is repeated several times with the result that the width of each of the barriers g.sub.1, g.sub.2, g.sub.3, . . . becomes about 100 .mu.m. Accordingly, in this case, the width of each of the spaces 5a, 5b, 5c, . . . becomes about 100 .mu.m, but a 70 .mu.m portion thereof is shielded by each of the anode electrodes x.sub.1, x.sub.2, x.sub.3, . . . so that the width of light emission or glow display capable of being observed is only 15 .mu.m on each sides of each of the anode electrodes x.sub.1, x.sub.2, x.sub.3, . . . or 70% of the width of the discharge light emission or glow portion is shielded by the anode electrodes x.sub.1, x.sub.2, x.sub.3, . . . .